Boranes, heteroboranes and metallacarboranes, all named as boron clusters, offer an alternative to typical organic molecules or organic molecular materials. Carbon and boron share the important property of self-catenation thus these elements can produce individually large and sophisticated molecules. Boron clusters and organic molecules display electronic, physical, chemical and geometrical characteristics manifestly different. These differences highlight the complementarity of organic molecules and boron clusters, and therefore the feasibility or necessity to produce hybrid molecules incorporating both types of fragments. To join these two types of fragments, or alternatively these two types of molecular compounds, tools are needed. In this review the current methods of producing boron clusters with carbon, B-C, nitrogen, B-N, phosphorus, B-P and sulphur bonds, B-S, are indicated. As there are many existing borane clusters of different sizes, heteroboranes and metallacarboranes, the revision of methods to generate the B-C, B-P, B-S, and B-N bonds has been restricted to the most widely used boron clusters; [B12H12](2-), dianionic and an example of a borane, 1,2-C2B10H12, neutral and an example of a heteroborane, and [Co(C2B9H11)2](-), monoanionic and an example of a metallacarborane.

We synthesized Na(2)[B(12)H(12)] by a solid state procedure and thermal decomposition of Na[B(3)H(8)], and calculated from a first-principles approach the thermodynamic and structural properties. In particular, the calculated enthalpy of formation of the monoclinic structure, at T = 0 K, of -1086.196 kJ mol(-1) showed that it is a very stable compound. Therefore, in case it were formed during the thermal decomposition of NaBH(4), it would be rather considered a product, which, in addition, prevents the subsequent re-hydrogenation process because of its low reactivity to hydrogen. We reported the isotherms of absorption of H(2), O(2), and H(2)O, calculated both theoretically and experimentally.

The combination of Ca(BH4)2 and MgH2 materials results in a composite with remarkable hydrogen storage properties. However, full reversibility upon the (re)hydrogenation reaction has not yet been achieved. The poor reversibility is shown to be linked to the formation of stable intermediate phases or side products upon decomposition. In this work, we show, for the first time, the clear experimental evidence of CaB12H12 among the decomposition products of a Ca(BH4)2 + MgH2 composite. A combination of 11B Magic Angle Spinning–Nuclear Magnetic Resonance (11B{1H} MAS NMR), ex situ X-ray diffraction (XRD) and Rietveld analysis are presented. An assessment of the (de)hydrogenation and (re)hydrogenation reactions of Ca(BH4)2 + MgH2 composite is reported. The experimental results provided in this work highlight the reasons for the limited reversibility observed in the Ca(BH4)2 + MgH2 composite upon (re)hydrogenation.

No abstract

Easy as A, B-C: B-C cross-coupling on [3,3'-Co(8-I-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))](-), [1](-), the best specimen of metallacarboranes, is easily produced in a reaction mediated by Li(+) in the absence of a transition-metal catalyst. Pure RLi or a mixture of Li reagents (tBuLi+RLi) is adequate to produce the B-C bond. Notably, a threshold of RLi (or tBuLi+RLi)/[1](-), 2:1, is required to initiate the B-C coupling, which acts, at least in part, as a source of soluble Li(+).

Benzene and pyrene can be synthetically linked to [o‐COSAN]− keeping their aromaticity. In contrast, naphthalene and anthracene are extruded in the same reaction. We have proven that extrusion is only favorable if the number of Clar's π‐sextets remains constant. Thus, Clar has the answer to whether an attached polycyclic aromatic hydrocarbon to [o‐COSAN]− is extruded or not.

Benzene and pyrene can be synthetically linked to [o-COSAN] À keeping their aromaticity. In contrast, naphthalene and anthracene are extruded in the same reaction. We have proven that extrusion is only favorable if the number of Clar's π-sextets remains constant. Thus, Clar has the answer to whether an attached polycyclic aromatic hydrocarbon to [o-COSAN] À is extruded or not.

Review: 82 refs.